"Since Kunal Ghosh is a prime witness of the scam, it is the imperative for Bengal police to be more alert and monitor him 24/7.

"The jail authority's approach therefore raises further questions - whether it was a suicide attempt or a political conspiracy to suppress evidence? Also it is important to know how the sleeping drugs were slipped into his room ?" Singh said in a statement.

CBI should investigate the suicide attempt and ensure a safer custody of the prime accused in Saradha scam, he said.

Ghosh had allegedly tried to commit suicide by consuming sleeping pills in the early hours in Presidency correctional home where he is lodged.

Singh said many people suspected a political motive behind Ghosh's arrest last year after he began exposing several senior leaders of Trinamool Congress for their alleged involvement in the scam.

Referring to Ghosh claiming that his life was in danger in the custody of Bengal police and his threat to commit suicide, he said, "CBI being independent will follow their own line of investigation.

However, what is alarming is that Bengal police and the jail authorities allowed Kunal Ghosh to commit suicide inside the jail after he had already made his intention clear."